[zapyourrideguy]

my Honda Civic with 45 180ah Calbs (grey cells) in storage. My friend was charging it once a month but cells still managed to go almost to zero. DC-DC converter and orion bms was the load. The cells I checked were below .5 volt the whole pack reads 30 volts, should be 144v I’m thinking they are toast. I was researching this and ran across a forum post about bringing LiFePo4 to zero to increase capacity. It was about A123 cells .
Most posts/research seem to indicate they are gone. The one cell I started to charge very slow has come up to voltage and is staying there when idle, but haven’t tested capacity yet.

 

[zapyourrideguy]

Thank you
I am using an RC charger to control voltage and amperage of charge. So set charger no higher than 3.5 at say 10 amps
(.1C would be 18 Amps). Once I got to 2.5 volts, I have been charging first to 3.4 for 2+ hours now at 3.5v amperage is already tailing down below 10 amps with no detectable heating of cell at all.

 

[zapyourrideguy]

After charging to 3.45 I started a charge discharge cycle test.
In cycling between 3.1 and 3.5 I get 170ah on 1st charge and 200 milliamps on discharge and then a similarly low charge (a few hundred milliamps with the Icharger at 20 amps. the Icharger quickly goes through 5 cycles that way.
It looks like high IR?
for a capacity test what bottom voltage should I keep to? I cycled 2 cells this way when charged to 3.5 they both settle at 3.34 volts after 12 hours. both cells stayed stone cold throughout the process.
Both cells took in 160 ah to 170 ahs.

 

[zapyourrideguy]

What do you think on Internal Resistance? and the Icharger short cycle time? Is a 20 amp draw pulling voltage down below 3.1 thus stopping the discharge cycle sound like a battery with decent capacity but high IR or am I missing something? I will capacity test next and then an IR test Thank you for your help.

 

[zapyourrideguy]

Will this Lipo ESR meter handle these larger cells? In the literature/and photograph of unit it only says 100 to 25,000 mAH.